1. Field of the Invention
The present invention relates to packaging suitable for die having inputs or outputs operating at frequencies up to the Gigahertz range, with leads having one or more distinct impedances, which allows for optimization for signal, power, or desired interconnect properties.
2. Description of Related Art
Electronic devices and components are operating at ever increasing speeds and over increasing frequency ranges. Popular semiconductor package types use wire bonds that can connect to a substrate or leadframe, which in turn can connect to second level interconnects, vias, substrate or package traces, solder balls, or the like, for connection to a printed circuit board (PCB) of an electronic device.
However, differing lead lengths can result in significant changes in impedance. This can include changes to series inductance. One solution is to partially compensate these lumped inductance changes with shunt capacitance, but such lumped structures tend to create non single-valued impedance behavior over frequency. Another solution is to attempt to select wire lengths that provide average impedance instead of optimized impedance. Unfortunately, this is difficult to achieve practically, and can result in poor performance for various connections that could benefit from impedance far from average.